I have read it and love it - I also liked his other books, The Omnivore's Dilemma and The Botany of Desire.
I haven't read those. Years ago I read his book,
A Place of My Own, about building a small "writer's shed" in his backyard.
Overall, I think he made a good case in
In Defense of Food against "nutritionalism", and about going back to thinking of food
as food. Books of this sort can sometime be a bit dry, but this was so well written that it was actually enjoyable to read.
I also think he had some good suggestions for changing the way we eat (although I'm not sure about the gardening one); but as he admits himself, it's not going to be easy.
I read the book a few weeks ago, but at the time didn't really think about it changing my way of looking at food as much as it has. I'm presently rereading the latter parts of the book about changing the way we shop and eat. I don't expect to be able to do everything he suggests, but I am going to try to eliminate highly processed foods and high fructose corn syrup from my diet as much as possible.
